first roughen up the surface with a nailfile or fine sandpaper
when done with the first step take the plasic cup and fill it with the glitter you want ( you can add multiple colours and then mix them together) after that add the glue. stir it well and there you have what you need to pimp your shoes.
take a bit of the mixture and put it on your shoes don't add thick layers just wait for it to dry and then if you are not happy with the result add another layer of glitter and glue.
cover the parts that you want to and if you are finished wait for it to dry. I had glue that was white and dried up colourless so wait for the result to see if you are happy with it.
if you are happy with the result and want the glitters to stay put take a bit of hairspray and spray it on
if you are totally finished you should be left with something like this